When Eric, Kitty and Red are all sitting at the kitchen table discussing how Eric should deliver the news of Mr. Bonkers' death, Red says, "You go over there and you say, 'Hey, I'm a cat killer. I'm a...' [bursts into laughter and snickers] 'I murdered your cat!'". That was not how Kurtwood Smith was supposed to deliver the line. Instead, he unintentionally broke character and laughed at the obscurity of the line by adding, "I murdered your cat!", but he quickly pulled himself back together.
Fez: "Hyde, which one's your favorite Angel?" Fez is referring to the TV show, "Charlie's Angels", which aired from 1976 to 1981. Tanya Roberts (Midge Pinciotti) co-starred in the fifth season of "Charlie's Angels". Fez also has a dream ("Fez's Angels"), as he's going under for surgery, which is a spoof of "Charlie's Angels". He's "Fez", and Laurie, Jackie and Donna are his "Angels".
Ivan Goff's and Ben Roberts' original idea for "Charlie's Angels" was to have a trio of women: one blonde, one brunette and one redhead. That idea is realized in the fantasy segment with Jackie as the brunette, Laurie as the blonde and Donna as the redhead.